Bindable Function script are not working properly?

2 problems:

1. You needed to pull lines 09-13 of the second script out of the for loop, since it was returning an answer before reaching the end of the adms table.

2. In line 07 of the first script, you store the result of the invoked function in variable ifadm but are checking a different variable ifadmin on the next line to decide to open the door or kill the player. ifadmin was a typo, so the variable was nil, causing the if statement to evaluate to false and always skip to line 11.

Here is the fixed code without any other edits:

-- First Script
part = script.Parent

part.Touched:connect(function(hit)
    humanoid = hit.Parent:FindFirstChild("Humanoid")
    if humanoid then
        plrName = hit.Parent.Name
        ifadmin = game.Workspace.AdmList.List:Invoke(plrName)
        if ifadmin == true then
            part.CanCollide = false
        else
            humanoid.Health = 0
        end
    end
end)


-- Second Script
adms = {"YouCheater"}
script.List.OnInvoke = function(name)
    isadm = false
    for i, v in ipairs(adms) do
        if name == v then
            isadm = true
            break
        end
    end
	if isadm == true then
        return true
    else
        return false
    end
end

I would also add a debounce to your Touched event handler, since it will fire a lot just from one player running into the door.